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Re: Pacmakers and Tesla coils = bad??

However, building a GOOD Faraday cage is non trivial.  Any wire that
penetrates the surface (including the twists in the chicken wire) can
provide a pathway for RF energy.  The single best thing you can do is
provide a good conductive counterpoise/ground underneath the coil so that
the current induced by the RF field has somewhere "safe" to go (i.e. back
into the other end of the coil).


-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Monday, February 14, 2000 4:32 PM
Subject: Re: Pacmakers and Tesla coils = bad??


>Original Poster: rdgraaf-at-ocenl.nl
>
>There is a very simple solution: it's called a cage of Faraday...
>Chicken wire will do the trick. Naturally this will cost some
>performance, but hey what is more important? btw, will also protect
>your own and your neighbours Hifi, TV, Computer, etc.!
>
>Ruud de Graaf
>Holland
>
>
>Date forwarded: Sun, 13 Feb 2000 20:14:02 -0700
>Date sent:      Sun, 13 Feb 2000 20:14:43 -0700
>To:             tesla-at-pupman-dot-com
>Subject:        Re: Pacmakers and Tesla coils = bad??
>Forwarded by:   tesla-at-pupman-dot-com
>From:           Tesla List <tesla-at-pupman-dot-com>
>
>> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>>
>> Hi Stan,
>>
>> WOW!!!  When I was reading about pacemakers, it was implied that they
>> could be accidently triggered by a number of things.  I was not really
>> "sure" a TC could do it but the things they described seemed like it
would
>> be very possible.  However, this is proof that a 15/60 coil can trigger
the
>> defibrillator types at 25 feet.  The people that have these are warned by
>> their doctors what the jolt they give is like so they will be somewhat
>> prepared.  This is especially important if they are driving or something
>> (Mark mentioned that they would normally be unconscious, but perhaps that
>> can be programmed).  Pacemakers can also be stunned into safe and default
>> modes if their logic detects something is wrong.  This may go unnoticed
but
>> they may not be able to operate as needed in such a fail safe state.  The
>> equipment that "talks" to these pacemakers may be able to detect and
count
>> the number of times they are affected.
>>
>> There apparently are no official levels or standards of EM interference
>> for these things.  Different brands appear to be affected more or less.
>> They are somewhat "hardened" against normal EMI but a Tesla coil is
>> obviously quite abnormal in most EMI respects.  CERN calls out 0.5mT but
I
>> am not sure that is well based.
>>
>> http://www.cern.ch/CERN/SafetyGuide/Part3/42.Magnetic.html#warning
>>
>> It would be nice if we could come up with a "safe" distance or some
>> maximum EM level but there appears to be no such data that would apply to
>> all manufacturers of pacemakers.  It looks like the only thing we can go
by
>> now is "Keep pacemakers FAR away from any TC!"
>>
>> Many thank for this very important post on this subject!
>>
>> Cheers,
>>
>> Terry
>>
>>
>>
>> At 09:15 PM 02/13/2000 -0500, you wrote:
>> >I witnessed first-hand what a TC can do to a modern pacemaker.  A fellow
>> >was about 20-25ft from a running 15/60 coil.  It ran for maybe 30
>> >seconds then suddenly he shook violently and dropped down on to his
>> >knees.  Apparently, the gap misfired or whatever and for a second the
>> >frequency of the output was abnormal and triggered his pacemaker.  If I
>> >remember right his delivered 5J.  Whatever it delivered, it scared the
>> >holy heck out of me and was very painful for him.  Fortunately, the
>> >shock had no ill effects on his rhythm.
>> >
>> >Obviously this situation could have been disastrous.  The TC could have
>> >triggered his pacemaker and sent his heart into an irregular beat, or
>> >perhaps worse could have quietly destroyed his pacemaker and would have
>> >never been noticed until it failed to shock when it was really needed.
>> >
>> >IMHO it's just not worth it.  Keep pacemakers FAR away for any TC!
>> >
>> >-Stan
>> >
>> >Tesla List wrote:
>> >>
>> >> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>> >>
>> >> Hi Mark,
>> >>
>> >> I just want to thank you for adding this sort of expert addition to
all
>> >> this.  I got onto this pacemaker thing by accident, but the stuff I
saw
>> >> really worried me!!
>> >>
>> >> Having a pacemaker zap someone would be sort of unpleasant.  However,
>> >> having it do ANYTHING it is not supposed to be doing is a real
concern.
>> >> Tesla coils would be almost a worst case situation to find these ultra
>high
>> >> tech gizmos dealing with.
>> >>
>> >> When they were just simply bipolar devices they were probably pretty
>immune
>> >> to a lot of things.  However, the are now really sophisticated and
they
>> >> could do a lot of harm if they were to get "confused".  I think we
need to
>> >> be extra careful of these things now!
>> >>
>> >> Cheers,
>> >>
>> >>         Terry
>> >>
>> >
>>
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